N,N-Dimethyl formamide facilitated formation of hexagonal boron nitride from boric acid

• We successfully synthesized h-BN plates by a reaction of DMF-BA with ammonia.
• The crystallinity and compositions of the DMF-BA relative to BA were varied greatly.
• The pure h-BN was completely formed at 1500 °C by using the DMF-BA as B sources.
• The G.I. value indicates that the as-obtained h-BN is a promising candidate as raw material of c-BN.
• The thermostability indicates that the h-BN would possess better applications in the air.

In this paper, we report on a promoting novel process for the formation of h-BN plates by using N,N-dimethyl formamide-treated boric acid (DMF-BA). Using this B source, the formation of h-BN can be indeed improved greatly compared to using pure boric acid (BA). This method effectively reduces the content of boric acid and amorphous boric oxide, enhancing the transformation rate of h-BN. For preparation of pure h-BN, it can obviously lower the resultant temperature without further purification process. Via graphitization index (G.I.) calculation and thermostability analysis, the pure h-BN plates obtained from the DMF-BA would be a promising candidate for raw material of c-BN and low-temperature applications in the air.

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